Cam followers are used in many applications for translating rotational movement into linear movement, such as cam followers used in conveyor systems. During usage, inner and outer races of cam follower bearing assemblies can be subjected to relatively high bearing stresses. Hence, it is desirable to harden the roller raceways to improve bearing life. This commonly is accomplished by forming the inner and outer bearing races from high carbon, bearing grade steel and hardening the raceway areas, such as by heat treatment.
Such steel bearing races, however, are highly subject to corrosion, particularly when the cam followers are used in working environments in which they are subjected to liquids, corrosive chemicals, or other contaminants. Corrosion on external surfaces of the cam follower can be viewed by a user as adversely affecting the performance. Internal corrosion, of course, can lead to seizure and failure of the relatively moveable bearing components.
Efforts to overcome the corrosion problem by forming the cam follower components of a corrosion resistant metal alloy, such as austenitic stainless steel (type 300 series) typically are not practical since such corrosion resistant steel can not be hardened to the extent necessary for satisfactory bearing life. Alternately, forming the cam follower components of martensitic stainless steels, such as 440 C, provides a bearing grade steel which is hardenable. However, the corrosion resistant properties are less than that of the 300 series stainless steels. Proposals for protecting the bearing races of the cam follower from corrosive contaminants also have not been effective since the laterally extending stud or mounting shaft of the cam follower is an extension of the inner bearing race, and hence, can not be easily contained.